Vacuum-actuated transfer device and assembly apparatus

ABSTRACT

Piston rod and piston have passageways for introducing vacuum into a cylinder at both sides of the piston. Cylinder has an open end with a sealing surface which advances against an article and then retracts with the article as a result of vacuum acting on differential effective areas of the piston. The device is mounted on a movable head so that it transports the article from a feed shuttle to a workpiece, and tools on the head secure the article to the workpiece.

United States Patent Ginther l VACUUM-ACTUATED TRANSFER DEVICE ANDASSEMBLY APPARATUS [72] Inventor: Gary D. Ginther, Leonard, Mich.

[73] Assignee: Clyde Corporation, Troy, Mich.

[22] Filed: Oct. 14, 1970 [21] Appl. No.: 80,701

[52] U.S. Cl ..214/1 BT, 294/64 R, 214/8.5 F [51] Int. Cl ..B66c 1/02[58] Field of Search ..294/64 R; 214/1 BS, 1 BT,

214/1 BH, 1 EV [56] References Cited UNITED STATES PATENTS 3,227,070l/l966 Brigham ..2l4/1 BV mmwn [451 Oct. 3, 1972 2/1971 Cvacho ..2l4/lBV X 3/1971 Sirvet ..294/64 R Primary Examiner-Gerald M. ForlenzaAssistant Examiner-George F. Abraham Attorney-Barnes, Kisselle, Raisch &Choate [57] ABSTRACT 14 Claims, 7 Drawing Figures PATENTED "0T 3 I 2SHEEI 2 BF 3 INVENTOR. GARY D. GINTHER ATTORNEYS This invention relatesgenerally to apparatus for assembling articles and more particularly toa device which utilizes vacuum to pick up and hold an article while itis transferred from one location to another, as from a feeding stationto a workpiece.

Conventional vacuum pick-up and transfer devices are moved bodily fromone location to another location where they engage the workpiece to betransferred. After the workpiece has been secured to the device byvacuum, the entire device is then moved bodily in the opposite directionto transfer the workpiece. This necessitates the operation of somemechanism, valving, circuitry, or the like to cause a reversing of thedirection of movement of the transfer device after it has engaged theworkpiece.

A principal object of the present invention is to provide a vacuumpick-up or transfer structure which is improved over conventionalstructures in that it is simpler, less expensive, and, nevertheless,functions automatically to reverse its own direction immediately uponestablishing a vacuum draft connection with a workpiece.

In general, the invention contemplates the use of a piston and pistonrod mounted within a cylinder, the piston dividing the cylinder into asealed chamber containing the piston rod and an open-ended chamber onthe opposite side of the piston. The piston rod and piston are providedwith passageways which introduce vacuum into both chamberssimultaneously. The open end of the cylinder has a seal for engaging aworkpiece. When vacuum is introduced into the chambers, the cylinder isadvanced toward a workpiece by vacuum in the sealed chamber. When thesealing surface engages the workpiece, the workpiece itself seals theopenended chamber; and the cylinder with the workpiece retracts becauseof the larger effective area of the piston exposed to the vacuum in theopen end of the cylinder. One form of the invention is shown in theaccompanying drawings.

FIG. 1 is, in general, a side elevational view of assembly apparatusincorporating the present invention, parts being shown in section and inphantom to illustrate structural details and functioning.

FIG. 2 is a schematic view of circuitry to the transfer device.

FIG. 3 is an enlarged scale fragmentary plan view of a part of theapparatus.

FIG. 4 is an enlarged scale, fragmentary, elevational view of theapparatus with parts broken away and shown in section to illustratestructural details.

FIG. 5 is a view generally similar to FIG. 4 showing the vacuum transferdevice in a different condition.

FIG. 6 is a fragmentary elevational view illustrating the step ofsecuring two workpieces together.

FIG. 7 is a sectional view on line 7-7 of FIG. 4.

Selected for illustration of the invention is an apparatus 10 forassembling cover plates 12 on the bodies 14 of oil pumps forautomobiles. Each cover plate has a plurality of ears 16 each with anopening 18 through which screws 20 pass for threaded engagement intapped openings 22 in ears 24 on pump body 14.

The apparatus includes a bed 26 which supports a frame 28 having a top30. Supported beneath top 30 are a pair of ways 32 within which a slide34 moves to the left and right as FIG. 1 is viewed. Top 30 has a slot 36through which a post 38 on slide 34 projects, the

post having lugs 40 which engage threadedly adjustable stops 42, 44 onupwardly projecting portions 46, 48 respectively of frame 28. Stops 42,44 limit the extent of movement of slide 34. Mounted on top 30 of theframe is a magazine 50 which contains a stack of cover plates 12. Thebottom of magazine 50 is open so that the bottom cover plate thereinrests upon the top of slide 34. On top of the slide is a plate 52 whosepurpose is described below.

A crank 54 is pivotally mounted at 56 on pillow blocks 58 beneath slide34. One arm of the lever is connected by a clevis 60 to the piston rod62 of a pneumatic or hydraulic cylinder 64 mounted on frame 28. Theother arm of lever 54 has an extension 66 which carries a plurality ofupwardly projecting pins 68, 70. These pins project upwardly throughopenings 72, 74 in slide 34 for engagement within a correspondingplurality of cover plate openings 18 when crank extension 66 is rockedupwardly from the dotted-line position of FIG. 4 to the solid-lineposition.

The extent of upward rocking movement of extension 66 is adjusted bymeans of a threaded stop 75 which engages the underside of slide 34. Theextent of downward rocking movement is limited by engagement of a lug 77against the underside of slide 34, this lug being disposed on theopposite side of pivot 56 from extension 66. Slide 34 is provided with acentral vent hole 79 for a purpose to be described.

A stanchion 76 on bed 26 supports vertical ways 78 within which a slide80 moves, and a laterally projecting head 82 on the slide carries avacuum pick-up and transfer device 84, as well as four poweredscrewdriving tools 86 (only two appearing in FIG. 1). Screws 20 are fedone at a time to screwdrivers 86 through tubes 88 by suitable feedingequipment not forming a part of this invention, and the screwdrivers arefurnished with propelling compressed air through ducts 9 0. Vacuum isprovided to transfer device 84 through tubing 92.

A conveyor 94 carries a succession of oil pump bodies 14 beneath head82, the direction of movement being perpendicular to the plane ofFIG. 1. The pump bodies are secured to conveyor 94 by suitable meanssuch as clamps 96 and dowel pins 98. Vacuum transfer device 84 includesa piston 100 having a piston rod 102 fixedly mounted on head 82. Acylinder 104 surrounding piston 100 is mounted for axial movementrelative to the piston. The cylinder has a keyway 106 which embraces akey 108 projecting inwardly from a support 1 10 bolted to cross head 82as at 1 l2.

Cylinder 104 has an internal chamber 114 at the side of piston 100 fromwhich piston rod 102 projects. This chamber is pneumatically sealed byO-rings 116 and 118. The end portion 120 of cylinder 104 is open, andthis end portion is provided with a sealing surface which, in theillustrated apparatus, comprises a seal ring 122 of rubber, neoprene, orthe like.

Piston rod 102 has an internal passageway 124, one end of which isconnected to vacuum tube 92 at 126. Passageway 124 extendslongitudinally through piston 100 and at its opposite end has arestricted port 128 which opens through the end face 130 of the piston100 which is disposed toward open end 120 of cylinder 104.

Passageway 124 has a branch passageway 132 which opens into sealedchamber 1 l4.

Vacuum line 92 is placed under vacuum by any relatively simple circuitrysuch as that shown in FIG. 2 wherein pressure in an air line 134 isreduced by a pressure regulator and a simple two-way valve 136 controlsthe flow of air through line 134 to a conventional venturi-type vacuumtransducer 138 into which vacuum line 92 is connected.

In use, it may be assumed that conveyor 94 has brought a pump body 14into alignment beneath crosshead 82. Suitable conventional controls areoperated to actuate cylinder 64 and advance piston rod 62 and clevis 60to the left as FIG. 1 is viewed. Because of inherent friction in thesystem, this results initially in upward rocking movement of crankextension 66 so that pins 68, 70 pass upwardly through slide openings72, 74 and engage within cover plate openings 18.

Thereafter, slide 34 is advanced to the left and pins 68, 70 strip thebottom cover plate 12 out of magazine 50. The cover plate is carried tothe left until it is accurately aligned beneath cross head 82, at whichtime a lug 40 on post 38 engages stop 44. Slide plate 52, which hasabout the same thickness as cover plates 12, moves into supportingrelation beneath the remaining cover plates in magazine 50. The partsare now in the position shown in FIG. 3 and in dotted lines in FIG. 1with plate 12 positioned beneath vacuum device 84 and openings 18positioned beneath screws 20 previously fed to screwdrivers 86. In FIG.3, slide 34 is shown without a cover plate thereon.

Valve 136 is now opened; and in the diagram of FIG. 2, this is done bymoving the valve member from the closed position illustrated to an openposition wherein the arrow is aligned with adjacent portions of air line134. Air from the air line passes through venturi 138 which inducesvacuum in line 92, passageways 124, 132, and sealed chamber 114 withincylinder 104. This causes cylinder 104 to advance toward cover plate 12downwardly as the drawings are viewed until seal 122 engages the coverplate. This position is represented in dotted lines in FIG. 4.

A sealed chamber 140 is thereby created beneath lower face 130 of piston100, this chamber being defined by portions of cylinder 104, seal 122,cover plate 12, and O-ring 116. Air is immediately evacuated fromchamber 140 through port 128. The portion of plate 12 surrounded by seal122 in effect becomes a head of cylinder 104 having an effective areagreater than the effective area of piston 100 exposed to chamber 114,since the effective area of this piston portion is diminished by thecross-sectional area of piston 'rod 102.

Therefore, atmospheric air pressure on the underside of plate 12 forcesthe plate and cylinder 104 upwardly from the position of FIG. 4 to theposition of Fig. 5. During this movement, cover plate openings 18 passupwardly around screws 20. Openings 72, 74, and 79 in slide 34 providevents to facilitate penetration of air between the cover plate and theslide and consequent parting of the cover plate from the slide.

Advancement and retraction of cylinder 104 with plate 12 occurs in afraction of a second. Elsewhere herein, for the sake of convenience,this sequence has been described as resulting from introducing vacuuminto cylinder 104.

Restricted port 128 limits the flow of air from atmosphere throughpassageways 124, 132, 92 prior to engagement of seal 122 against coverplate 12 so that adequate vacuum can be maintained in chamber 114without an unduly high rate of air flow through venturi 138.

Cylinder 64 is now actuated to retract piston rod 62 and clevis 60.During the initial movement, extension 66 is rocked downwardly from thesolid-line position to the dotted-line position of FIG. 4; andthereafter, slide 34 is retracted to the solid-line position of FIG. 1at which a lug 40 on post 38 engages stop 42. During terminal movementof the slide, plate 52 retracts from under the stack of cover plates inmagazine 50 so that the bottom cover plate drops onto the top of theslide.

Suitable conventional controls and mechanism are now actuated to advancecrosshead 82 toward pump body 14 downwardly as the drawings are viewed.Transfer device 84 carries cover plate 12 downwardly into engagementagainst the top of pump body 14 and screws 20 enter the upperextremities of tapped openings 22 in the pump body. Screwdrivers 86 areactuated by suitable conventional controls and drive screws 20 intoopenings 22 as shown in FIG. 6.

Valve 36 is returned to the closed position of FIG. 2, relieving vacuumin cylinder 104 and crosshead is retracted upwardly to the position ofFIG. 1. Another set of screws 20 is fed into screwdrivers 86, and theapparatus is ready for another cycle of operation when a successive pumpbody 14 is conveyed into alignment with crosshead 82.

By utilizing a plurality of pins 68, 70, the rotative orientation ofcover plate 12 is properly maintained so that openings 18 pass over theawaiting screws 20 when the cover plate is elevated. Key 108 and keyway106 in the cylinder cooperate to maintain piston and cylinder 104 insubstantially the same relative rotative orientation so that cylinder104 does not tend to rotate a cover plate 12 being carried thereby. Thecover plate arrives at engagement with the pump body in proper positionfor unobstructed driving of screws 20 into the pump body.

Transfer device 84 is useful for transferring articles in general fromone location to another. The transfer device need not have the verticalorientation illustrated but is equally capable of functioning in ahorizontal or angled position. If an unusually large article is to betransferred, several vacuum transfer devices 84 could be utilized toengage different portions of the article. While the use of seal ring 122is convenient, the sealing surface at the open end of cylinder 104 canbe provided by any other convenient or suitable means such as simplymachining the open end surfaces of the cylinder accurately I claim:

1. A vacuum-actuated device for transferring articles comprising,

a relatively movable piston and cylinder, the cylinder having a sealedchamber at one side of the piston and another chamber at the other sideof the piston having a portion which defines porting open to theatmosphere,

said piston having a smaller effective area exposed to said one chamberthan to said other chamber,

passageway means adapted to place both of said chambers in communicationwith a vacuum source,

said porting being pneumatically closable responsive to engagement ofsaid portion with an article with which said device is adapted to beused.

2. The device defined in claim 1 wherein said porting is open in adirection axial of the cylinder.

3. The device defined in claim 2 wherein said porting is at an end ofsaid cylinder.

4. The device defined in claim 3 wherein said cylinder is substantiallyentirely open at said end to provide said porting.

5. The device defined in claim 4 wherein said end of aid cylinder isprovided with an annular seal positioned for engagement with saidarticle.

6. The device defined in claim 1 wherein a piston rod extends from saidone side of said piston to the exterior of said cylinder and providessaid one side with said smaller effective area.

7. The device defined in claim 6 wherein portions of said piston andpiston rod define said passageway means.

8. The device defined in claim 7 wherein said passageway means comprisesa passageway which extends longitudinally through said piston rod andpiston and opens into said other chamber, said passageway having abranch which opens into said sealed chamber.

9. The device defined in claim 1 wherein said porting comprises a singleopening defined by an open end of said cylinder, means providing asealing surface around said opening for engagement with said article,

a piston rod extending from said one side of said piston to the exteriorof said sealed chamber and providing said one side with said smallereffective area,

said passageway means comprising a passageway which extendslongitudinally through said piston rod and piston, said passagewayhaving one end adapted for connection to a source of vacuum and anotherend which opens into said other chamber, said passageway having a branchwhich opens into said sealed chamber.

10. The device defined in claim 9 wherein said other end of saidpassageway has an effective area smaller than that of said one end andsaid branch.

11. The device defined in claim 1 wherein a piston rod extends from saidone side of said piston and has a portion which projects exteriorly ofsaid sealed chamber, said piston rod portion being mounted on a support,said cylinder being movable relative to said piston rod and support,said piston rod providing said one side of said piston with said smallereffective area,

and in combination therewith feed means operable to present a saidarticle at a location aligned with said cylinder portion which definessaid porting, said portion being advanceable into engagement with saidarticle responsive to introduction of vacuum into said sealed chamberand being retractable with said article responsive to closing of saidporting upon engagement of said cylinder portion with said article.

12. The combination defined in claim 11 and including in addition areceptacle adapted to receive a said article, said support being movableto transport-said piston rod between said location and a positionadjacent said receptacle, said device being effective to deposit anarticle carried thereby on said receptacle res onsive to release ofvacuumjn said cylinder.

3. The combinatlon defined 2 wherein the ln claim direction of movementof said support between said location and position and the direction ofmovement of said cylinder relative to said piston are substantiallyparallel.

14. The combination defined in claim 12 wherein said receptaclecomprises a workpiece to which a said article is to be applied, saidsupport carrying tool means, said tool means being operable to secure tosaid workpiece a said article deposited thereon by said device.

1. A vacuum-actuated device for transferring articles comprising, arelatively movable piston and cylinder, the cylinder having a sealedchamber at one side of the piston and another chamber at the other sideof the piston having a portion which defines porting open to theatmosphere, said piston having a smaller effective area exposed to saidone chamber than to said other chamber, passageway means adapted toplace both of said chambers in communication with a vacuum source, saidporting being pneumatically closable responsive to engagement of saidportion with an article with which said device is adapted to be used. 2.The device defined in claim 1 wherein said porting is open in adirection axial of the cylinder.
 3. The device defined in claim 2wherein said porting is at an end of said cylinder.
 4. The devicedefined in claim 3 wherein said cylinder is substantially entirely openat said end to provide said porting.
 5. The device defined in claim 4wherein said end of aid cylinder is provided with an annular sealpositioned for engagement with said article.
 6. The device defined inclaim 1 wherein a piston rod extends from said one side of said pistonto the exterior of said cylinder and provides said one side with saidsmaller effective area.
 7. The device defined in claim 6 whereinportions of said piston and piston rod define said passageway means. 8.The device defined in claim 7 wherein said passageway means comprises apassageway which extends longitudinally through said piston rod andpiston and opens into said other chamber, said passageway having abranch which opens into said sealed chamber.
 9. The device defined inclaim 1 wherein said porting comprises a single opening defined by anopen end of said cylinder, means providing a sealing surface around saidopening for engagement with said article, a piston rod extending fromsaid one side of said piston to the exterior of said sealed chamber andproviding said one side with said smaller effective area, saidpassageway means comprising a passageway which extends longitudinallythrough said piston rod and piston, said passageway having one endadapted for connection to a source of vacuum and another end which opensinto said other chamber, Said passageway having a branch which opensinto said sealed chamber.
 10. The device defined in claim 9 wherein saidother end of said passageway has an effective area smaller than that ofsaid one end and said branch.
 11. The device defined in claim 1 whereina piston rod extends from said one side of said piston and has a portionwhich projects exteriorly of said sealed chamber, said piston rodportion being mounted on a support, said cylinder being movable relativeto said piston rod and support, said piston rod providing said one sideof said piston with said smaller effective area, and in combinationtherewith feed means operable to present a said article at a locationaligned with said cylinder portion which defines said porting, saidportion being advanceable into engagement with said article responsiveto introduction of vacuum into said sealed chamber and being retractablewith said article responsive to closing of said porting upon engagementof said cylinder portion with said article.
 12. The combination definedin claim 11 and including in addition a receptacle adapted to receive asaid article, said support being movable to transport said piston rodbetween said location and a position adjacent said receptacle, saiddevice being effective to deposit an article carried thereby on saidreceptacle responsive to release of vacuum in said cylinder.
 13. Thecombination defined in claim 12 wherein the direction of movement ofsaid support between said location and position and the direction ofmovement of said cylinder relative to said piston are substantiallyparallel.
 14. The combination defined in claim 12 wherein saidreceptacle comprises a workpiece to which a said article is to beapplied, said support carrying tool means, said tool means beingoperable to secure to said workpiece a said article deposited thereon bysaid device.